Guy Hutchins of Trox describes how an old established refrigerant is being employed to cool the very
THE introduction of blade servers to the data storage market has enabled significantly more processing power to be concentrated in increasingly smaller units.

As a result this technology is now featuring prominently in the planning of next generation data centres and banking communities. With the advantages, however, come drawbacks and the blade servers greater requirement for cooling.

Ensuring data storage mechanisms work without overheating is an increasing priority as businesses rely ever more on information and communication technology particularly where breakdowns can cost millions of pounds per hour.

Traditionally, computer room environments have been controlled by a series of computer room air conditioning (CRAC) units, positioned around the perimeter, pushing our cooled air at high air-change rates. These units have an upper limit of 1-1.5kW/m2. With the power draw of a typical cabinet being 3-4.5kW, one cabinet requires a floor area of around 3m2.

The increased power densities of blade servers mean that a typical cabinet could have a power consumption of 20-30kW, which is beyond the capability of conventional CRAC units.

The challenge for designers is, therefore, the effective and constant removal of heat from the units to prevent temperatures rising and the servers overheating and crashing.

With this in mind, Trox Advanced IT Cooling Systems (Trox AITCS) launched a revolutionary cooling solution for business-critical blade servers, which utilises carbon dioxide as a risk-free cooling solution.



Carbon dioxide is a perfect cooling medium for IT applications because it:

• Is electrically benign and therefore poses no danger to servers or cabling.

• Offers seven times the cooling capacity of chilled water and, allows lower volume flows and therefore smaller diameter distribution pipe work.

• Saves up to 30% in energy by using less compressor power and CO2 pumping power.

• Results in no temperature rise as heat is absorbed during a “phase change”.

• Consumes less power for cooling, making it available for powering IT.

• Is a low cost gas in abundant supply as a waste by-product of industrial processes. It can therefore be considered as having a negative GWP in IT cooling applications. The power saving will reduce the CO2 emissions at the power station: for a 250kW system this may be as much as 290 tonnes per year.

• Is non-flammable and has a zero ozone depleting rating – successfully meeting World Health Organisation regulations for refrigerants.

• Is more efficient than air and water-cooling alternatives, so the 'footprint' of data centres can be reduced by 50-70%, saving valuable space in increasingly crowded computer rooms.

The system’s principle philosophy is to supply liquid CO2 to each cabinet and employ heat absorption, rather than provide cooling, thus creating a more intrinsically resilient and energy-efficient solution. With 1kg of CO2 absorbing seven times more energy than water, the system was designed to absorb heat at the rear of the cabinet as it is rejected by the servers.

Even when the cabinet door is open, around 60-70% of the server heat is absorbed by the unit. The 30-40% heat that spills out into the aisle raises the local ambient temperature by around 1-2°C. This is then absorbed by adjacent cabinets.





Trox AITCS

01842 763051